diff --git a/libraries/DataFlash/LogFile.cpp b/libraries/DataFlash/LogFile.cpp
index 1dc449f0ec..e7f9d9f794 100644
--- a/libraries/DataFlash/LogFile.cpp
+++ b/libraries/DataFlash/LogFile.cpp
@@ -282,7 +282,8 @@ void DataFlash_Class::Log_Write_GPS(const AP_GPS &gps, uint8_t i, uint64_t time_
         vacc          : (uint16_t)MIN((vacc*100), UINT16_MAX),
         sacc          : (uint16_t)MIN((sacc*100), UINT16_MAX),
         have_vv       : (uint8_t)gps.have_vertical_velocity(i),
-        sample_ms     : gps.last_message_time_ms(i)
+        sample_ms     : gps.last_message_time_ms(i),
+        delta_ms      : gps.last_message_delta_time_ms(i)
     };
     WriteBlock(&pkt2, sizeof(pkt2));
 }
diff --git a/libraries/DataFlash/LogStructure.h b/libraries/DataFlash/LogStructure.h
index 42795ecd18..bddf2652a8 100644
--- a/libraries/DataFlash/LogStructure.h
+++ b/libraries/DataFlash/LogStructure.h
@@ -79,6 +79,7 @@ struct PACKED log_GPA {
     uint16_t sacc;
     uint8_t  have_vv;
     uint32_t sample_ms;
+    uint16_t delta_ms;
 };
 
 struct PACKED log_Message {
@@ -909,8 +910,8 @@ struct PACKED log_SRTL {
 #define ESC_LABELS "TimeUS,RPM,Volt,Curr,Temp"
 #define ESC_FMT   "Qcccc"
 
-#define GPA_LABELS "TimeUS,VDop,HAcc,VAcc,SAcc,VV,SMS"
-#define GPA_FMT   "QCCCCBI"
+#define GPA_LABELS "TimeUS,VDop,HAcc,VAcc,SAcc,VV,SMS,Delta"
+#define GPA_FMT   "QCCCCBIH"
 
 // see "struct GPS_State" and "Log_Write_GPS":
 #define GPS_LABELS "TimeUS,Status,GMS,GWk,NSats,HDop,Lat,Lng,Alt,Spd,GCrs,VZ,U"